This invention is directed to a hydrolyzed proteinaceous milk solid which contains both whey and casein proteins.
Milk is a unique food stuff in that it contains proteins, lipids and carbohydrates along with trace amounts of certain inorganic elements including calcium, magnesium, potassium, sodium and phosphorus. Further, it also contains certain vitamins. The production of milk for the new born is a specific mammalian adaptation with the milk of any particular species normally fully meeting all of the nutritional requirements of the infants of that species.
Man has utilized the milk of certain domesticated animals not only for the milk itself, but also for the production of cheese, butter and other milk products. While the general composition of milk is essentially the same in all mammalian species, the concentration of certain constituents of the milk vary among the species.
Bovine milk contains about 3 to 4% protein. The casein component of the bovine milk protein constitutes about 80% of the total protein. The remaining protein is divided among certain whey proteins with the principal one being .beta.-lactoglobulin.
It was recognized in antiquity that the casein protein of bovine milk could be separated from the "whey" fractions by in situ acidification of milk utilizing enzyme extracts or by the direct addition of acid to the milk. For the preparation of casein from milk, after skimming the cream off the top the milk is acidified either by the addition of acid or by an enzyme. Below about pH 4.7 the casein precipitates as "curd" leaving a clear liquid, the "whey".
The harvesting of casein from milk utilizing either acid or an enzyme precipitation while efficient for recovering the casein protein from the milk, does not recover any whey protein. After acid enzyme precipitation of casein from milk, normally the whey fraction is discarded. This thus constitutes a waste of up to 20% of the protein content of the milk. It has been suggested as, for instance, Phillips, et al. U.S. Pat. No. 4,218,490, to harvest the whey protein content of milk utilizing ion exchange resins. Additionally, whey proteins have been isolated utilizing micropore filters having a pore size fine enough to retain the whey protein particles. While both of these processes are certainly utilitarian, they both require special apparatus, i.e. either ion exchange resins or micropore filters, and thus can not be broadly practiced.
In U.S. Pat. No. 4,545,933 entitled Hydrolyzed Protein Composition and Process Utilized in Preparation Thereof, assigned to the same assignee as this application, the inventor, John H. Ernster describes a process for hydrolyzing casein protein utilizing caustic solutions of sodium or potassium hydroxide. The hydrolyzed protein produced by the process of this patent has certain unique properties which are useful in the preparation of certain processed food products. The starting materials suggested for the process of U.S. Pat. No. 4,545,933 is acid precipitated casein, that is casein which contains no whey protein.
It has increasingly been recognized that over indulgence of certain animal fat is deleterious to the health of man. Unfortunately the fats or lipid content of certain food stuffs contribute to the palatability of the food product. Some of the richness and taste characteristics of many dessert items result from their lipid or fat content. More often than not, if the fat or lipid ingredients are excluded from a recipe the final product simply does not retain the characteristics of the original product and thus is unacceptable to the consumer.